Heater element fitting for pressurized tank



1966 R. N. COATES ETAL 3,

HEATER ELEMENT FITTING FOR PRESSURIZED TANK Filed 001;. 21, 1964 F|G 2 FIG ROBERT N. COATES JOHN T. BAILLARGEON INVENTORS.

ATTORNEYS United States Patent 3,283,940 HEATER ELEMENT FITTING FOR PRESSURIZED TANK Robert N. Coates, 8251 W. Mercer Way, Mercer Island, Wash, and John T. Baillargeon, Seattle, Wash., said Baillargeon assignor to said Coates Filed Oct. 21, 1964, Ser. No. 405,460 3 Claims. (Cl. 220-46) The present invention relates generally to pressurized tank fittings and more particularly to a novel means for fitting a heating element to the curved dome or other curved surface of a pressurized tank, such as a hot water tank.

Many problems have been encountered in providing a suitable pressure sealed fitting for mounting internal heating elements in pressurized water tanks and the like which are usually cylindrical in shape. The most economical and acceptable tank construction is that of utilizing a noncorrosive metal such as bronze or the like with a welded part-spherical head on each end of the tank. With this construction, the spherical heads of the tank may be made from the same weight of metal utilized in forming the cylindrical body of the tank with no added reinforcements necessary. Such tanks may be under a pressure of approximately 100 p.s.i. and higher depending on the particular use. In the past, it has been necessary to provide a flattened surface on the tank wall for mounting an internal heating element fitting. As can be appreciated, any flattening of the surface of the tank wall results in a weakening of the wall structure and, in addition, accounts for added expense in constructing a tank.

Since the most eflicien-t arrangement is to mount the heating elements vertically within the tank, the conventional prior art method is to provide a flat rather than a part-spherical end plate on a cylindrical tank for mounting the elements. Since the end plate is flat, it must be several times heavier than the curved walls of the body of the tank order to withstand the internal pressures which adds greatly to the cost of producing the tank. Overall, the problem of providing pressure sealed fittings for heating elements has not been satisfactorily solved and the cost of installing such heating elements accounts for a major portion of the cost of tank construction. Likewise, due to the complexity of such prior art fittings, a certain amount of skill is required in replacing a worn out element thus adding additional expense to the maintenance of pressurized tanks.

According to the present invention, a cylindrical pressurized tank may be constructed with a part-spherical dome and means are provided whereby heater fittings may be effectively mounted directly to the curved surface of the part-spherical dome. In accordance with the teachings of the present invention, the heater fitting is simplified by forming an opening or openings in the tank dome with amounting and sealing flange located about the opening and formed integral with the material of the dome Wall. The heater element structure is then mounted and sealed directly on the flange provided.

The primary object of the present invention is, therefore, to provide a simplified form of fitting for mountin-g heating elements and the like to pressurized tank walls.

Another object of the present invention is to provide a fitting of the character described which is highly simplified in form, economic -to manufacture and yet effective for sealing against internal tank pressures.

Another object of the present invention is to provide a fitting of the character described which is adapted for mounting on curved tank surfaces enabling a part-spherical dome tank construction.

Yet another object of the present invention is to provide a tank fitting of the character described wherein a continuous mounting and sealing flange is provided which is integral with the material of the tank dome itself so as to avoid the necessity for drilling, welding, or performing other operations which weaken the tank walls.

Still another object of the present invention is to provide an integral reinforced flanged opening in a tank wall which is adapted for cooperation with the mounting structure of an integral heating element.

Other more particular objects and advantages of the invention will, with the foregoing, appear and be understood from the following description and claims, the invention consisting of the novel construction and adaptation and combination of parts hereinafter described and claimed. Reference is made now to the accompanying drawings, in which:

FIG. 1 is a perspective view of a portion of a pressurized tank showing a heating element installed;

FIG. 2 is a cross sectional view taken along lines 22 of FIG. 1; and

FIG. 3 is a cross sectional view similar to FIG. 2 illustrating a second form of the invention.

Referring now to the drawing wherein like reference numerals indicate identical parts in the various views, FIG. 1 illustrates an electrical connector block indicated generally at 1 fitted to the part-spherical dome 2 of a conventional pressurized water tank 3. The connector block 1 serves to mount the electrical resistance heating element assembly 4 which extend into the body of the tank as indicated. Although FIG. 1 shows only one connector assembly and heating element in place, a plurality of additional openings 5 may be provided in the dome of the tank for mounting additional heating elements. As will be presently explained, flange structures are provided about the openings 5 and are formed directly from the material of the dome 2. The flange structures are shaped so as to cooperate with the details of the connector assemblies 1 to provide a pressure seal in fitting the connectors to the dome 2.

According to the present invention the tank 3 may be provided with the part-spherical dome 2 which, in practice, is formed separately from the tank body 3 and is then welded to the tank as indicated at 6. The openings 5 will be formed in the tank dome 2 prior to its attachment to the tank body 3. Although the present invention is illustrated as being applied to a part-spherical dome 2 of the tank, it will be understood that the invention applies equally well to any curved or irregular surface of a tank body to which a fitting of the character under consideration is to be mounted.

In preparing the dome 2, the desired number of openings 5 will be formed in the material depending on the number of heating elements to be installed. Each opening is provided with a surrounding flange 7 which may be formed at the time the openings are made. The openings 5 and flanges 7 may be formed by any well known metal forming apparatus known in the art and the fabrication may include the steps of punching and extruding the neck of the flange and forming the lip of the flange with a curling die. As indicated in FIG. 1, the openings 5 are made circular for ease of manufacture and the flange '7 is a continuous evenly curved annular flange. FIG. 2

shows the flange 7 in cross section which includes an outwardly directed cylindrical neck portion 8 which smoothly curves into a flared annular lip 9. It will be understood, of course, that the exact curvature between the neck 8 and the lip 9 may be varied somewhat as desired. It is also to be noted that the angle or curvature of the lip 9 may be varied without departing from the spirit of the present invention.

The electrical connector block assembly 1 normally includes a mounting plate 10 which is generally flat and may be of any shape or outline depending upon the particular installation. The plate 10 serves to support an insulator block 11 and a continuous tubular heating element assembly 4. The insulator block 10 is suitably connected with a resistance heating element contained within the assembly 4, not shown, and provides connector posts 12 for connecting the electrical leads. The plate 10 will also include a plurality of drilled openings 13 suitable for locating the clamping bolts 14 for a purpose to be described. It will be noted that the structure of the connector block thus far described is conventional structure widely used in connection with mounting tank heaters.

As will be appreciated by those familiar with the prior art, the problem involved is that of efliciently sealing the standard connector block structure described to the surface of the tank to enable the tank to be pressurized in use. FIG. 2 illustrates the fitting utilized according to one embodiment of the present invention. As shown in FIG. 2, a flat gasket 15 having a continuous sealing surface is assembled on the bottom side of the plate 10 about the upper end of the heating element assembly 4. The gasket 15 may .be made from any suitable deformable and elastic material such as rubber or its equivalent and will include holes for the passage of the clamping bolts 14. The heating element assembly 4 may be passed through the opening in the tank dome and the plate 10, with its gasket 15, seated directly on the lip portion 9 of the flange 7. It will also be noted that the plate is of sufficient dimensions to allow the bolt 14 to be positioned a slight distance from the outer edge of the lip 9. Two identical gripping members 16 and 17 are provided with each member 16 and 17 having tapped openings 18 for receiving the clamping bolts 14. Each of the members 16 and 17 may extend substantially half way around the outside surface of the cylindrical neck portion 8 of the flange and will be provided with a curved edge 19 which conforms with the curvature of the outside surface of the flange. Each of the members 16 and 17 will also include a raised edge portion 20 on its upper surface for contacting the bottom side of the gasket and for accommodating the thickness of the lip 9. Sealing of the connector block is accomplished by turning the clamp bolts 14 to tighten the gripping members 16 and 17 so as to compress the gasket 15 which forms a seal about the annular face and edge of the lip 9.

It is also to be noted that no weakening of the tank wall occurs in the area of the openings 5 with the structure described. Due to the fact that the neck of the flange 7 is cylindrical in shape and is formed by a continuous extruded portion of the tank wall, an inherent reinforcing of the wall results about the openings. It has been experienced in practice that the simplified seal construction according to the present invention is eflicient in providing a pressure seal for internally pressured tanks of any desired size and capacity. The formation of the flange 7 and the simplified clamping structure permit the construction of internally heated pressurized tanks at a cost much reduced from any known prior art fitting.

FIG. 3 illustrates a second embodiment of the invention utilizing a different form of seal between the annular lip 9 and the bottom face of the mounting plate 10. The

of the flange. The gripping members 16 and 17 are then clamped against the bottom of the mounting plate 10 by use of the bolts 14 as previously described to secure the mounting plate to the flange 7. Those familiar with the application of the O-ring seals will readily appreciate the sealing action which takes place between the O-ring 21, the bottom face of the plate 10 and the flange 7. To illustrate, as the tank is pressurized from within, the deformable O-ring member 21 will be caused to expand and deform into the 'junction between the lip 9 and the bottom of the plate 10. As the internal pressure in the tank is increased, the seal 21 is urged more tightly into place. Thus, the more pressure introduced into the tank, the more eflicient the seal becomes.

As will be appreciated by those familiar with the prior art involved, the present invention provides significant improvements in heater element fittings of the character described. The arrangement and types of structural components utilized within the invention may be subjected to numerous modifications well within the purview of this invention and applicant intends only to be limited to a liberal interpretation of the specifications and appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A fitting structure for mounting a heating element to the curved end wall of a pressurized tank comprising; a cylindrical neck extending outwardly from said curved end wall and defining an opening therein, a continuous annular flange formed on the outer end of said neck and including a continuous outwardly flared lip portion, said neck and said flange being integral with and formed from material extruded from said curved wall, a heating element mounting plate having a substantially flat surface for cooperation with said flange, a plurality of gripping members encircling the neck and contacting the underside of the lip portion of said flange, each of said gripping members having a depression in the portion of the upper surface thereof along the edge adjacent the neck, said depression having a depth equal to the flange thickness and forming a seat for the flange, the remaining portion of the upper surface of said gripping member providing a raised contacting portion, compressible seal means acting between said flange and the flat surface of said plate for sealing the plate to the flange, and means for clamping said gripping members together with said lip being received in the depressions in said gripping members.

2. The structure according to claim 1 wherein said seal means comprises a flat gasket located between said plate and said lip, said gasket being compressed by said clamping means to form a pressure tight seal.

3. The structure according to claim 1 wherein said seal means comprises a continuous O-ring of compressible elastic material, said O-ring being located at the juncture of said plate and said lip and responsive to pressure within said tank for sealing the plate to the flange.

References Cited by the Examiner UNITED STATES PATENTS 1,579,672 4/1926 Strecker 22046 2,179,476 11/1939 Andrus.

FOREIGN PATENTS 144,087 12/ 1930 Switzerland.

THERON E. CONDON, Primary Examiner. GEORGE E. LOWRANCE, Examiner. 

1. A FITTING STRUCTURE FOR MOUNTING A HEATING ELEMENT TO THE CURVED END WALL OF A PRESSURIZED TANK COMPRISING; A CYLINDRICAL NECK EXTENDING OUTWARDLY FROM SAID CURVED END WALL AND DEFINING AN OPENING THEREIN, A CONTINUOUS ANNULAR FLANGE FORMED ON THE OUTER END OF SAID NECK AND INCLUDING A CONTINUOUS OUTWARDLY FLARED LIP PORTION, SAID NECK AND SAID FLANGE BEING INTEGRAL WITH AND FORMED FROM MATERIAL EXTRUDED FROM SAID CURVED WALL, A HEATING ELEMENT MOUNTING PLATE HAVING A SUBSTANTIALLY FLAT SURFACE FOR COOPERATION WITH SAID FLANGE, A PLURALITY OF GRIPPING MEMBERS ENCIRCLING OF SAID FLANGE, EACH OF SAID GRIPPING SIDES OF THE LIP PORTION OF SAID FLANGE, EACH OF SAID GRIPPING MEMBERS HAVING A DEPRESSION IN THE PORTION OF THE UPPER SURFACE THEREOF ALONG THE EDGE ADJACENT THE NECK, SAID DE- 